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VulnerabilityPublished Updated

CVE-2024-21643: AzureAD azure-activedirectory-identitymodel-extensions-for-dotnet · Code Injection

Affects AzureAD azure-activedirectory-identitymodel-extensions-for-dotnetSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High : upgrade to 6.34.0 soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
2.2% chance of exploitation in 30 days – higher than 82% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.34.0
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Jan 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade microsoft.identitymodel to 6.34.0.

Affected software

ProductAffectedFixed in
NuGetmicrosoft.identitymodelpkg:nuget/microsoft.identitymodelOther threatsAffected
  • <6.34.0
Fixed in
  • 6.34.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately assess their use of Microsoft.IdentityModel.Protocols.SignedHttpRequest in their .NET applications, particularly those implementing federated identity with SignedHttpRequest or SignedHttpRequestValidator. The primary mitigation is to upgrade all affected Microsoft.IdentityModel packages to version 6.34.0 or higher for the 6.x branch, or 7.1.2 or higher for the 7.x branch. Additionally, organizations should audit their codebases and configurations to ensure that the 'jku' claim is not blindly trusted or that additional validation is performed on URLs referenced by this claim. Implementing strict allowlists for JWKS URLs, validating the domain and protocol, and restricting outbound HTTP requests from application servers can reduce the attack surface. Network-level controls such as web application firewalls (WAFs) and egress filtering can help detect and block suspicious HTTP requests triggered by exploitation attempts. Monitoring application logs for anomalous SignedHttpRequest validation failures or unexpected HTTP GET requests can provide early detection of exploitation attempts. Finally, organizations should review their incident response plans to include scenarios involving code injection and SSRF attacks targeting authentication components.

Description

IdentityModel Extensions for .NET provide assemblies for web developers that wish to use federated identity providers for establishing the caller's identity. Anyone leveraging the `SignedHttpRequest`protocol or the `SignedHttpRequestValidator`is vulnerable. Microsoft.IdentityModel trusts the `jku`claim by default for the `SignedHttpRequest`protocol. This raises the possibility to make any remote or local `HTTP GET` request. The vulnerability has been fixed in Microsoft.IdentityModel.Protocols.SignedHttpRequest. Users should update all their Microsoft.IdentityModel versions to 7.1.2 (for 7x) or higher, 6.34.0 (for 6x) or higher.

References

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